Expandable coil spinal implant

ABSTRACT

Coiled spinal implants for disc, vertebral body, and spinal motion segment replacement or reconstruction comprise a plurality of loops and spaces between the loops, with the loops formed of a hollow material and having a plurality of apertures or a longitudinal gap that extend(s) through the sidewalls of the loops and into the hollow center. The coiled implants include one or more balloons within the hollow center, the spaces between the coil loops, and/or within the central void that the coil surrounds. Filling the balloon expands the loops and thereby increases the height of the coil. Bone graft material or bone cement may be deployed from the apertures or gap.

FIELD

The disclosure relates generally to spinal implants, and in particular,to implants configured as an expandable coil with a balloon interspersedbetween or within the loops of the coil, which when inflated with afluid expands the coil to facilitate spinal reconstruction, particularlywhen needed to correct lesions or diseases of the vertebral body, adisc, and at least one spinal motion segment, also known as a functionalspinal unit.

BACKGROUND

In the spine, vertebrae provide the rigidity and support of the spinalcolumn, and the intervertebral discs provide flexibility and shockabsorption during movement. In some individuals, the intervertebraldiscs may be damaged from trauma, and/or may lose their integrity due todegeneration. Degenerated and damaged discs negatively affect theflexibility and load bearing capacity of the spine, and may cause painand discomfort in subjects, and may inhibit the ability of the subjectto move or lift objects.

To restore function of degenerated or damaged discs, such discs aretypically surgically removed, at least in part, and replaced with aprosthetic disc. Prosthetic discs may take the form of an implant, whichbridges adjacent vertebrae together and assumes the function of thenatural disc. Such implants often include bone or a material thatfacilitates bone growth, in which case the implants support fusion oftwo adjacent vertebrae via new bone growth. There remains a need toprovide implants for replacing intervertebral discs that re-establishand maintain a natural spinal alignment.

In some cases, bone tumors or significant bone trauma necessitatepartial or entire removal of a vertebral body. There is also a need toprovide implants that provide for a three dimensional reconstruction ofvertebral bodies that restore lost height, fill cavities, and providelong term stabilization of the reconstructed vertebrae.

SUMMARY

The disclosure features spinal implants that may be used for vertebralbody reconstruction and/or intervertebral disc replacement. In general,the implants comprise an expandable coil, and the coil comprises a topand bottom, and is formed from a hollow tube having a first end, asecond end, and side walls that define a lumen. The first end and/or thesecond end may be open, or may be closed. The coil comprises a pluralityof loops formed out of the hollow tube, and vertically adjacent loopshave a space between their respective lower and upper sidewalls. Thecoil thus comprises a plurality of loops and a plurality of spaces.

In some aspects, the implants comprise a plurality of apertures throughthe sidewalls that extend into the lumen. In some aspects, the implantscomprise, instead of a plurality of apertures, a gap through thesidewalls that extends into the lumen. The gap extends longitudinallyfrom the first end to the second end, and is present on either an upperor lower surface of the tube that has been formed into loops.

The implants may comprise at least one balloon interspersed throughoutand thereby occupying the space between vertically adjacent loops. Insome aspects, the balloon is housed within the lumen until it isdeployed. The balloon may be deployed from the lumen, through the gap,and into the space between vertically adjacent loops. When in the spacebetween vertically adjacent loops, and when filled, the balloon pushesthe loops of the coil apart in an upward and downward direction, therebyexpanding the coil. For example, as it fills and expands to its outwardcapacity, the balloon pushes on the lower surface of the loop directlyabove the balloon, pushing that lower surface (and loop) upward, and theballoon also pushes on the upper surface of the loop directly below theballoon, pushing that upper surface (and loop) downward). When the coilis expanded, the implant has a height that approximates the height of anintervertebral disc and/or the height of a vertebral body, and in someaspects, approximates the height of two vertebrae and at least one disc(e.g., a spinal motion segment or functional spinal unit). In someaspects, a spinal motion segment comprises two adjacent vertebralbodies, the facet joint created by their articular processes, theintervertebral disc between them and associated soft tissue. Theintervertebral disc and the facet joints (one on each side of themidline) allow for motion in flexion, extension, side bending androtation at the level of the motion segment. The at least one balloonmay be compliant, semi-compliant, or non-compliant.

The hollow tube may be comprised of a flexible metal, including a metalthat has a shape memory capacity, enabling stress-inducedsuperelasticity, and reversible deformation up to 8-10% strain. Suitablemetals include titanium, steel, aluminum, or alloy such as nitinol.

A bone graft material or bone cement may be present in the lumen, or maybe introduced into the lumen by way of a tool that is releasablyconnected to the first end, and is also operably connected to a supplyof bone graft material or bone cement. Thus, the tool may take the bonegraft material or bone cement from the supply and insert it into thelumen of the implant. The bone graft material may be cancellousautograft bone, allograft bone, demineralized bone matrix (DBM), bonemorphogenic protein (BMP), or any combination thereof. The bone cementmay comprise calcium phosphate or hydroxyapatite.

In some aspects, the implants comprise a plurality of balloons,including two, three, four, five, six, seven, eight, or more balloons.These balloons are interspersed through and occupy the space betweeneach loop, including after such balloons are deployed from the lumen.Any of the balloons may comprises a single chamber, or a plurality ofchambers. The balloons also comprise an opening that allows air or afluid to pass into the chamber in order to fill the balloon. To theopening, a tool may be releasably connected, and this tool may also beoperably connected to a supply of air or a fluid. A fluid to beinserted, including injected, into the balloons may comprise water,saline, a contrast medium, a hydrogel, or a bone cement. The fluid maybe in a liquid form when inserted into the balloon chamber, andpolymerizable, crystalizable, or capable of solidifying once insertedinto the balloon and/or inside of the body upon implantation of theimplant. The one or plurality of balloons may be affixed to the loops byway of an adhesive, though in some aspects an adhesive is not used.

The disclosure also features methods for augmenting or reconstructing avertebral body, and methods for repairing or replacing an intervertebraldisc, and methods for reconstructing a spinal motion segment. Themethods generally comprise implanting the implant, such as any implantdescribed or exemplified herein, into a vertebral body (e.g., a void ina vertical body produced by a corpectomy procedure whereby a portion ofthe vertebral bone is removed) or intervertebral space, or removedspinal motion segment, filling the balloon with an amount of a fluidsufficient to deploy the balloon from the lumen and/or expand the coiland increase the height of the implant to a desired height, optionallydeploying a bone graft material or bone cement from the plurality ofapertures or gap, and/or first and second openings into the vertebralbody or intervertebral space, and optionally, removing the expandablecoil from the vertebral body or intervertebral space. The coil may beremoved from the vertebral body or intervertebral space after deployingthe bone graft material or bone cement, in cases where a bone graftmaterial or bone cement was deployed.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is best understood from the following detaileddescription when read in connection with the accompanying drawings. Itis emphasized that, according to common practice, the various featuresof the drawings are not to scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.Included in the drawings are the following figures:

FIG. 1A and FIG. 1B each show a perspective view of an embodiment of acoiled spinal implant without a balloon interspersed between the coilloops;

FIG. 2A and FIG. 2B each show a perspective view of an embodiment of acoiled spinal implant with a balloon interspersed between the coilloops;

FIG. 3A shows a vertebrae with a coiled implant positioned on centralarea of the vertebral endplate;

FIG. 3B shows a vertebrae with two coiled implants, each positioned at alateral area of the vertebral endplate;

FIG. 4 shows a coiled implant in the place of a vertebral body removedfrom a copectomy procedure;

FIG. 5A shows a cross-sectional representation of the deployment of aballoon out of the lumen of a loop of the coil, with the gap in thesidewall being relatively narrow;

FIG. 5B shows a cross-sectional representation of the deployment of aballoon out of the lumen of a loop of the coil, with the gap in thesidewall being relatively large, approximating a half pipe; and,

FIG. 6 shows a close-up of a the deployment of a balloon out of thelumen of a loop of the coil, with the gap in the sidewall aimingdownward toward the upper surface of an adjacent loop.

DETAILED DESCRIPTION

Various terms relating to aspects of the present disclosure are usedthroughout the specification and claims. Such terms are to be giventheir ordinary meaning in the art, unless otherwise indicated. Otherspecifically defined terms are to be construed in a manner consistentwith the definition provided in this document.

As used throughout, the singular forms “a,” “an,” and “the” includeplural referents unless expressly stated otherwise.

The terms subject and patient are used interchangeably. A patient may beany animal, including mammals such as companion animals, laboratoryanimals, and non-human primates. Human beings are preferred.

The disclosure features devices, systems, and methods for replacing orreconstructing an intervertebral disc, or replacing or reconstructing atleast a portion of a vertebrae such as a vertebral body, or replacing orreconstructing a spinal motion segment in a patient in need thereof. Thedevices, systems, and methods may find use, for example, in spinalreconstruction, repair, or fusion procedures. A foundational feature isan expandable coil with balloons interspersed throughout the spaces ofthe coil. Larger expandable coils may be used for reconstruction ofvertebral bodies. Smaller expandable coils may be used in theintervertebral space for disc replacement. Even larger expandable coilsmay be used for reconstruction of spinal motion segments spanning atleast two vertebral bodies and at least one intervertebral disc.

The components of the expandable coil can be fabricated from anysuitable material or combination of materials. Materials includeplastic, polymers, metals, and composites, preferably medical orsurgical grade, and preferably biocompatible, as well as natural orsynthetic bone. Non-limiting examples of suitable polymers includepolyetheretherketone (PEEK), polyamineimide (PAI), polyethyleneimine(PEI), polyphenylsulfone (PPSU), polyoxymethylene (POM), and ultra highmolecular weight polyethylene (UHMW-PE). Non-limiting examples ofsuitable metals include titanium, tantalum, aluminum, surgical-gradesteel, as well as alloys, including titanium alloys such as nitinol(nickel-titanium alloy), Ti-6Al-4V (TAV), and Ti-6Al-7Nb (TAN), andcobalt-chromium alloys. Nitinol is preferred. Carbon may also be used tofabricate at least part of the implant coil. Preferably, the material issufficiently flexible so that the coil may expand.

Referring now to the drawings, in which like reference numbers refer tolike elements throughout the various figures that comprise the drawings,FIG. 1 shows an example of an expandable coil implant 10. The coiledimplant 10 comprises a top 12 and a bottom 14, and a plurality ofexpandable loops 16. As the implant 10 is a coil, the coiled implant 10also includes a plurality of spaces 18 that are interspersed between theloops 16. The spaces 18 are vertically oriented between adjacent loops16. For example, each loop 16 comprises a sidewall 20 that has an upper,lower, outer, and inner surface, and each space 18 is located directlybeneath the lower surface of a loop 16 and directly above an uppersurface of the loop 16 that is closest to the upper loop 16 in avertical plane. The spaces 18 are between vertically adjacent loops, notbetween horizontally adjacent loops; a central void 19 is betweenhorizontally adjacent loops. The coiled implant 10 comprises a first end11, generally located at the top 12, and a second end 13, generallylocated at the bottom 14. The first end 11 and second end 13 maycomprise a point, or may be flat, and they each are preferably blunt.The first end 11 and second end 13 may comprise an edge, barb, orprojection that engages and digs into vertebral bone, for example, tohelp hold the implant 10 in place.

The coiled implant 10 loops 16 are preferably hollow, and thus comprisetube-shaped sidewalls 20 that surround a lumen 22 (FIG. 5a and FIG. 5B).The tube-shaped sidewalls 20 may comprise a substantially round,elliptical, quadrilateral, pentagonal, hexagonal, heptagonal, oroctagonal shape, though a shape with any number of sides may beemployed. FIG. 1 shows the sidewalls 20 in a substantially round shape.In some aspects, the implant 10 may also include a plurality ofapertures 24 that pass through the sidewalls 20 and into the lumen 22.In addition, in some aspects, at least one of the first end 11 and thesecond end 13 may comprise an opening 15, 17.

A first tool 100 may releasably engage either or both of the first end11 or second end 13 of the implant 10. The first tool 100 may comprise acatch or snare, or simply be compatibly shaped to fit over or into theopening 15 or 17, including with a friction fit. The first tool 100 maycomprise a pump, and or may be operably connected to a supply of bonegraft material, and/or to a supply of air or fluid.

In some aspects, the implant 10 does not include a plurality ofapertures 24 through the sidewalls 20. Instead, in such aspects, thesidewalls 20 comprise a gap 26 through the sidewalls 20 and into thelumen 22. The gap 26 runs substantially the entire length of the implant10, for example, the gap extends from the first end 11 to the second end13. The gap 26 may be on any of the upper, lower, outer, or innersurface of the sidewalls 20 of the loops 16. Preferably, the gap 26 ison either the upper surface or lower surface of the sidewalls 20. FIG. 6shows an example of the gap 26 on the lower surface of the sidewalls 20.

In some aspects, the spaces 18 between the loops 16 are preferablyoccupied by a balloon 30 or membrane 30. An example of this embodimentis shown in FIG. 2. The balloon 30 or membrane 30 may be wedged betweenthe sidewalls 20 of vertically adjacent loops 16, for example, with afriction fit, and/or may be affixed to the sidewalls 20 by way of anadhesive.

In some aspects, the balloon 30 or membrane 30 is not present in thespaces 18 at first, for example, during the implantation process itself.In such aspects, the balloon 30 or membrane 30 is housed within thelumen 22 of the implant 10, and is deployed from the lumen 22 into thespaces 18 once the implant 10 is placed in the desired location withinthe vertebrae or intervertebral space. While housed within the lumen 22,the balloon 30 or membrane 30 is preferably substantially not inflated.In such aspects, the implant 10 comprises the gap 26, and the balloon 30or membrane 30 is deployed from the lumen 22, through the gap 26, andinto the spaces 18 of the implant 10. See, e.g., FIG. 6. The gap 26 maycomprise any suitable width. See, e.g., FIG. 5A and 5B. The balloon 30or membrane 30 may be deployed, for example, by filling it with air or afluid as described herein. The filling of the balloon 30 or membrane 30forces it through the gap 26, where it continues to be filled, becomeswedged within the spaces 18 and thereby contacts the upper and lowersurfaces of vertically adjacent loops 16, and as it continues to befilled, forces vertically adjacent loops 16 upward and downward,respectively, thereby expanding the coil.

A second tool 200 may releasably engage an open end of the balloon 30 ormembrane 30, whether the balloon 30 or membrane 30 is within the lumen22 and/or in the spaces 18 and/or in the central void 19. The secondtool 200 may comprise a tube, including a flexible plastic or rubbertube, or even a more rigid metal tube. For example, such a tube mayengage an opening on the balloon 30 or membrane 30, including with afriction fit. The second tool 200 may comprise a pump, and or may beoperably connected to a supply of air or fluid.

The first tool 100 may be used to hold the implant 10, for example, toplace the coiled implant 10 at its desired location within the vertebralbody or in the intervertebral space. The first tool 100 may also be usedto move the implant 10 in order to position the implant 10 at itsdesired location. In some aspects, the first tool 100 may be used todeliver a bone graft material or bone cement through the first end 11 orsecond end 13 and into the lumen 22 of the implant 10. For example, thea bone graft material may be extruded through the first tool 100 andthrough the opening 15 or 17 (depending on if the first tool 100 isattached to the first end 11 or second end 13) of the coiled implant 10to which the first tool 100 is attached. The bone graft material or bonecement may then pass into and through the lumen 22, and may exit thelumen 22 through the plurality of apertures 24, or the gap 26, as wellas the opening 15 or 17 that is not connected to the first tool 100.Thus, the plurality of apertures 24 and the openings 15 or 17 deploy thebone graft material or bone cement. In some aspects, the gap 26 may beused to deploy the bone graft material or bone cement.

More than one balloon 30 or membrane 30 may be used. The balloon 30 ormembrane 30 may be fabricated from any suitable material. For example,the material may comprise a biocompatible plastic, polymer, rubber,composite, foil, or combination thereof. The balloon 30 or membrane 30may be compliant or semi-compliant, for example, may expand uponfilling. The balloon 30 or membrane 30 may be non-compliant, forexample, may not substantially expand upon filling, although suchnon-compliant balloons 30 or membranes 30 may unfold if folded up. Theballoon 30 or membrane 30 may comprise a single volume or a plurality ofvolumes, for example, in the latter case, the balloon 30 or membrane 30may have a plurality of chambers that may be filled. The balloon 30 ormembrane 30 includes at least one opening in communication with eachchamber through with fluid or air may be inserted in order to fill thechamber. Once the balloon 30 or membrane 30 is filled to a desiredlevel, the opening may be closed, for example, with a stopper, tie,adhesive, seal, solder, or other suitable closure. The opening maycomprise a valve, including a self-sealing valve.

The balloon 30 or membrane 30 may be filled, for example, with suitableamount of air or a fluid. For example, the balloon 30 or membrane 30 maybe at least partially filled with air or a fluid such that the balloon30 or membrane 30 expands, thereby holding the balloon 30 or membrane 30in place in the inter-loop spaces 18 during insertion and placement ofthe implant 10. Once the implant 10 is seated in the desired locationwithin the vertebral body or the intervertebral space, the balloon 30 ormembrane 30 may be filled with additional air or liquid to furtherexpand the balloon 30 or membrane 30. As the balloon 30 or membrane 30is filled and expands, it exerts outward pressure on adjacent loops 16of the coil, and thereby forces the loops 16 apart from each other in anupward/downward direction about an axis X. As the loops 16 expand apart,the height H of the implant 10 increases. Increasing the height H of theimplant 10 enhances the fit of the implant 10 between vertebrae, andwhen used as a disc replacement in the intervertebral space, establishesthe desired distance between the endplates of adjacent vertebrae, forexample, to restore the natural distance formerly occupied by thenatural disc, or to establish an angle of lordosis.

Together, the balloon 30 or membrane 30 and the loops 16 may essentially“wall off” a center 19 of the implant 10, the center 19 beingessentially a void 19 surrounded by the loops 16 and spaces 18, whichspaces 18 may be occupied by a balloon 30 or membrane 30. Thus, in someaspects, a bone graft material, for example, such a material deployedthrough the apertures 24 and/or openings 15 or 17, may fill the void 19,being contained between the inner surface of the loops 16 and innersurface of the balloon 30 or membrane, and may make contact vertebralbone, and in some aspects, contact bone of adjacent vertebrae.

In some alternative embodiments, the balloon 30 or membrane 30 also ispresent in at least a portion of the void 19 in the center of the coil.Thus, the balloon 30 or membrane 30 may occupy some or all of the center19 of the coiled implant 10. Such a balloon 30 or membrane 30 may alsobe in at least one of the spaces 18 between the loops 16, or the balloon30 or membrane 30 may not occupy any of the spaces 18 between the loops16, and essentially be caged by the plurality of loops 16 thatconstitute the coil.

The bone graft material may be natural or synthetic, and may comprisecancellous autograft bone, allograft bone, collagen-hydroxyapatite,demineralized bone matrix (DBM), porous synthetic bone graft substitute,bone morphogenic protein (BMP), or combinations thereof. Any materialthat promotes bone growth and osseointegration may be used. The bonegraft material may be in the form of a paste, putty, or slurry. The bonegraft material may comprise growth factors. Numerous bone graftmaterials are commercially available, and are suitable for use inconnection with the implant 10.

The balloon 30 or membrane 30 may be filled by way of the second tool200, which may be attached to the open end of the balloon 30 ormembrane, and which thereby may deliver the air or fluid into theballoon 30 or membrane 30 chamber. The fluid may comprise a physiologicsaline solution, a radiopaque contrast solution, or may comprise water,or may comprise a hydrogel, or may comprise a polymerizable monomer orpolymer, or may comprise a bone cement, or may comprise a crystalizablematerial. Non-limiting examples of a bone cement comprise calciumphosphate (CaP) and/or comprise hydroxyapatite. Preferably, the fluid isbiocompatible. Preferably, the fluid provides for a cushioning effect,yet may bear some of the load forces from movement of the spine, forexample, when the subject moves, or lifts objects. For vertebralreconstruction, the fluid may be a bone cement, and provide less of acushioning effect and provides more of a load bearing function. Thefluid may comprise polymethyl methacrylate (PMMA). The fluid may be in aliquid form when inserted into the balloon chamber polymerizable,crystalizable, or capable of solidifying once inserted into the balloonand/or inside of the body upon implantation of the implant.

The coiled implant 10 comprises a height H (FIG. 1 and FIG. 2). Theimplant height H, expanded or unexpanded, is preferably measured fromthe surface of the top 12 to the surface of the bottom 14. Coiledimplants 10 for vertebral reconstruction may have comparatively largerheights H, which substantially approximate the height of the vertebralbody being reconstructed. Coiled implants 10 for disc replacement mayhave comparatively smaller heights H, which substantially approximatethe height of the disc being replaced.

The height H of the non-expanded coiled implant 10 that is used for discreplacement (e.g., an intervertebral coiled implant 10) may be about 5mm to about 20 mm. In some aspects, the height H of the non-expandeddisc replacement implant is about 5 mm to about 10 mm, about 5 mm toabout 12 mm, about 5 mm to about 14 mm, about 5 mm to about 15 mm, about5 mm to about 16 mm, about 5 mm to about 18 mm, about 5 mm to about 20mm, about 7 mm to about 10 mm, about 7 mm to about 12 mm, about 7 mm toabout 14 mm, about 7 mm to about 15 mm, about 7 mm to about 16 mm, about7 mm to about 18 mm, about 7 mm to about 20 mm, about 9 mm to about 12mm, about 9 mm to about 14 mm, about 9 mm to about 15 mm, about 9 mm toabout 16 mm, about 9 mm to about 18 mm, about 9 mm to about 20 mm, about10 mm to about 12 mm, about 10 mm to about 14 mm, about 10 mm to about15 mm, about 10 mm to about 16 mm, about 10 mm to about 18 mm, about 10mm to about 20 mm, about 11 mm to about 13 mm, about 12 mm to about 14mm, about 12 mm to about 15 mm, about 12 mm to about 16 mm, about 12 mmto about 18 mm, about 12 mm to about 20 mm, about 13 mm to about 15 mm,about 14 mm to about 16 mm, about 14 mm to about 18 mm, about 14 mm toabout 20 mm, about 15 mm to about 17 mm, about 15 mm to about 18 mm, orabout 15 mm to about 20 mm. The unexpanded implant height may be lessthan 5 mm, or greater than 20 mm.

The expanded implant 10 may approximate the height of the intervertebraldisc being replaced, including a cervical, thoracic, lumbar, or sacraldisc. Once expanded, the height H of the coiled implant 10 used for discreplacement may be about 5 mm to about 35 mm. In some aspects, theheight H of the expanded implant is about 7.5 mm to about 10 mm, about7.5 mm to about 12 mm, about 7.5 mm to about 14 mm, about 7.5 mm toabout 15 mm, about 7.5 mm to about 16 mm, about 7.5 mm to about 18 mm,about 7.5 mm to about 20 mm, about 7.5 mm to about 25 mm, about 7.5 mmto about 27 mm, about 7.5 mm to about 30 mm, about 9 mm to about 12 mm,about 9 mm to about 15 mm, about 8 mm to about 16 mm, about 8 mm toabout 18 mm, about 8 mm to about 20 mm, about 9 mm to about 22 mm, about9 mm to about 24 mm, about 9 mm to about 25 mm, about 9 mm to about 30mm, about 10 mm to about 12 mm, about 10 mm to about 14 mm, about 10 mmto about 15 mm, about 10 mm to about 16 mm, about 10 mm to about 18 mm,about 10 mm to about 20 mm, about 10 mm to about 22 mm, about 10 mm toabout 24 mm, about 10 mm to about 26 mm, about 10 mm to about 28 mm,about 10 mm to about 30 mm, about 12 mm to about 16 mm, about 12 mm toabout 18 mm, about 12 mm to about 20 mm, about 12 mm to about 22 mm,about 12 mm to about 24 mm, about 12 mm to about 26 mm, about 12 mm toabout 30 mm, about 14 mm to about 18 mm, about 14 mm to about 20 mm,about 14 mm to about 22 mm, about 14 mm to about 24 mm, about 16 mm toabout 18 mm, about 16 mm to about 20 mm, about 16 mm to about 22 mm,about 16 mm to about 24 mm, about 18 mm to about 20 mm, about 18 mm toabout 22 mm, about 18 mm to about 25 mm, about 20 mm to about 22 mm,about 20 mm to about 24 mm, about 22 mm to about 26 mm, or about 23 mmto about 25.The unexpanded implant height may be less than 5 mm, orgreater than 35 mm.

The height H of the non-expanded coiled implant 10 that is used forvertebral body or spinal motion segment reconstruction (e.g., avertebral body coiled implant 10) may be about 10 mm to about 60 mm. Insome aspects, the height H may be about 10 mm to about 15 mm, about 10mm to about 20 mm, about 10 mm to about 25 mm, about 10 mm to about 30mm, about 10 mm to about 35 mm, about 10 mm to about 40 mm, about 10 mmto about 45 mm, about 15 mm to about 20 mm, about 15 mm to about 25 mm,about 15 mm to about 30 mm, about 15 mm to about 35 mm, about 15 mm toabout 40 mm, about 15 mm to about 45 mm, about 20 mm to about 25 mm,about 20 mm to about 30 mm, about 20 mm to about 35 mm, about 20 mm toabout 40 mm, about 20 mm to about 45 mm, about 25 mm to about 30 mm,about 25 mm to about 35 mm, about 25 mm to about 40 mm, about 25 mm toabout 45 mm, about 30 mm to about 40 mm, about 30 mm to about 45 mm, orabout 35 mm to about 40 mm.

The expanded implant 10 may approximate the height of the vertebral bodyor spinal motion segment being reconstructed, including a cervical,thoracic, lumbar, or sacral vertebral body, and in some aspects, also atleast one intervertebral disc. Once expanded, the height H of the coiledimplant 10 used for vertebral body reconstruction may be about 10 mm toabout 80 mm. In some aspects, the expanded height H may be about 10 mmto about 15 mm, about 10 mm to about 20 mm, about 10 mm to about 25 mm,about 10 mm to about 30 mm, about 10 mm to about 35 mm, about 10 mm toabout 40 mm, about 10 mm to about 45 mm, about 10 mm to about 50 mm,about 10 mm to about 55 mm, about 10 mm to about 60 mm, about 10 mm toabout 70 mm, about 15 mm to about 20 mm, about 15 mm to about 25 mm,about 15 mm to about 30 mm, about 15 mm to about 35 mm, about 15 mm toabout 40 mm, about 15 mm to about 45 mm, about 15 mm to about 50 mm,about 15 mm to about 55 mm, about 15 mm to about 60 mm, about 15 mm toabout 70 mm, about 20 mm to about 25 mm, about 20 mm to about 30 mm,about 20 mm to about 35 mm, about 20 mm to about 40 mm, about 20 mm toabout 45 mm, about 20 mm to about 50 mm, about 20 mm to about 55 mm,about 20 mm to about 60 mm, about 20 mm to about 65, mm about 25 mm toabout 30 mm, about 25 mm to about 35 mm, about 25 mm to about 40 mm,about 25 mm to about 45 mm, about 25 mm to about 50 mm, about 25 mm toabout 55 mm, about 30 mm to about 40 mm, about 30 mm to about 45 mm,about 30 mm to about 50 mm, about 30 mm to about 45 mm, about 35 mm toabout 40 mm, about 35 mm to about 45 mm, about 35 mm to about 50 mm, orabout 35 mm to about 60 mm.

Once the balloon 30 or membrane 30 is filled, the implant height H mayincrease up to about 100%, or in some aspects, up to about 125%, up toabout 150%, or up to about 175%. Preferably, the implant height Hincreases about 10% to about 50% relative to the unexpanded height H.The implant height H may increase about 10% to about 40%, about 10% toabout 33%, about 10% to about 30%, about 10% to about 25%, about 10% toabout 20%, about 10% to about 15%, about 15% to about 45%, about 15% toabout 40%, about 15% to about 33%, about 15% to about 30%, about 15% toabout 25%, about 15% to about 20%, about 20% to about 50%, about 20% toabout 40%, about 20% to about 33%, about 20% to about 30%, about 20% toabout 25%, about 25% to about 50%, about 25% to about 40%, about 25% toabout 33%, about 25% to about 30%, about 50% to about 05%, about 30% toabout 40%, or about 40% to about 50%, relative to the unexpanded heightH. In some aspects, the implant height H increases about 10%, about 15%,about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%,about 85%, about 90%, about 95%, about 100%, or more, relative to itsunexpanded height H.

In some aspects, the coiled implant 10 comprises a lordotic angle suchthat the height H on one side of the implant 10 is greater than theheight H on an opposing side of the implant 10. The greater height H andthe lesser height H may independently comprise a size described orexemplified herein.

The coiled implant 10 preferably has a substantially uniform width W.The width may be measured from the outer surface of a loop 16 on oneside of the implant 10 to the outer surface of a loop 16 on the opposingside of the implant 10. In embodiments where the coiled implant 10comprises a substantially circular shape, the width W comprises adiameter. The coiled implant may comprise non-circular shapes, includingoval shapes or elliptical shapes, or even irregular shapes.

The implant width W may be about 10 mm to about 70 mm. In some aspects,the width W may be about 10 mm to about 20 mm, about 10 mm to about 25mm, about 10 mm to about 30 mm, about 10 mm to about 35 mm, about 10 mmto about 40 mm, about 10 mm to about 45 mm, about 10 mm to about 50 mm,about 10 mm to about 65 mm, about 15 mm to about 20 mm, about 15 mm toabout 25 mm, about 15 mm to about 30 mm, about 15 mm to about 35 mm,about 15 mm to about 40 mm, about 15 mm to about 45 mm, about 15 mm toabout 50 mm, about 15 mm to about 55 mm, about 15 mm to about 60 mm,about 15 mm to about 65 mm, about 15 mm to about 70 mm, about 20 mm toabout 25 mm, about 20 mm to about 30 mm, about 20 mm to about 35 mm,about 20 mm to about 40 mm, about 20 mm to about 45 mm, about 20 mm toabout 50 mm, about 20 mm to about 60 mm, about 20 mm to about 65 mm,about 20 mm to about 70 mm, about 25 mm to about 30 mm, about 25 mm toabout 35 mm, about 25 mm to about 40 mm, about 25 mm to about 45 mm,about 25 mm to about 50 mm, about 25 mm to about 60 mm, about 30 mm toabout 35 mm, about 30 mm to about 40 mm, about 30 mm to about 45 mm,about 30 mm to about 50 mm, about 30 mm to about 60 mm, about 35 mm toabout 40 mm, about 35 mm to about 45 mm, about 35 mm to about 50 mm,about 35 mm to about 55 mm, about 40 mm to about 45 mm, about 40 mm toabout 50 mm, about 40 mm to about 55 mm, about 45 mm to about 50 mm,about 45 mm to about 55 mm, or about 45 mm to about 60 mm. Widths Wshorter than 10 mm or longer than 70 mm are possible. It is preferredthat the width W does not extend beyond the outer dimensions of thevertebrae.

In some aspects, the coiled implant 10 is preferably used for insertioninto the intervertebral space. Thus, once inserted, the top 12 andbottom 14 of the implant 10 contact adjacent vertebral endplate bone,with the implant 10 seated between these adjacent vertebral endplates,in the space formerly occupied by a damaged, diseased, or degenerateddisc. The coiled implant 10 may be inserted into the intervertebralspace of cervical, thoracic, lumbar, or sacral vertebrae, and the heightH may be according to the intended location of the implant within thespinal column (e.g., cervical, thoracic, lumbar, or sacral region of thespine).

In some aspects, the coiled implant 10 is preferably used for threedimensional reconstruction of a vertebral body. Thus, once inserted, thetop 12 and bottom 14 of the implant 10 approximate the missing portionof the vertebral body, with the implant 10 preferably seated within avertebral body, in the space formerly occupied by a damaged, diseased,or degenerated segment of the vertebral bone. The coiled implant 10 maybe inserted into a cervical, thoracic, lumbar, or sacral vertebrae, andthe height H may be according to the missing section of bone.

In some aspects, the coiled implant 10 is preferably used for threedimensional reconstruction of a spinal motion segment. Thus, onceinserted, the top 12 and bottom 14 of the implant 10 approximate themissing portion of two vertebral bodies and at least one intervertebraldisc, with the implant 10 preferably seated within in the space formerlyoccupied by a damaged, diseased, or degenerated segment of the vertebralbone and disc. The coiled implant 10 may be inserted into the space of acervical, thoracic, lumbar, or sacral vertebrae, and their respectiveintervertebral disc, and the height H may be according to the missingsection of bone and disc.

The implant 10 may be inserted into the body as part of spinal fusionprocedure, or may be inserted as a form of a disc prosthesis withoutparticipating in any fusion. In this latter case, for example, theimplant 10 occupies the intervertebral space, but does not facilitatenew bone growth or fusion of adjacent vertebrae. If not fused, theimplant 10 may be removed from the intervertebral space at some point inthe future. When used as part of a spinal fusion procedure, the implant10 includes bone graft material delivery, and it is this bone graftmaterial that facilitates new bone growth and osseointegration of theimplant 10.

In some preferred aspects, the material of which the implant 10sidewalls 20 are fabricated has elasticity and also comprises a shapememory. For example, the material may be used to form a coil outside ofthe body of the subject, and the coil may be straightened for insertioninto the subject, for example, to minimize the size of the incisionthrough which the implant passes during the insertion procedure, yet thestraightened coil returns to the coil shape once inserted into the body.A guide wire, including a flexible wire, may be used to guide theuncoiled implant 10 to its location in the disc space or in thevertebral body, and removed one the implant 10 is in a desired place,with removal of the guide wire allowing the coil to reform according tothe shape memory of the material from which the coiled implant 10 ismade.

In some aspects, the implant 10 comprises a temperature memory, e.g.,thermal memory. For example, an implant 10 with a thermal memory may bestraightened at room temperature, yet coiled at a heated temperature,including body temperature. In some aspects, the implant 10 comprises asuper-elastic memory. For example, a straight tube (e.g., nitinol) maybe pre-formed into a coil at high temperatures (e.g., 480-520° C.) andquenched, for example, in cooled water. The coiled tube may be forciblyuncoiled and inserted into/constrained by a straight cannula or sheath,yet when released from the straight cannula or sheath, the tubeautomatically re-coils, stemming from the super-elastic memory of thematerial from which the tube was fabricated.

The implant 10, whether in coiled form or in straightened form(including a guide wire, if used), may be inserted into the body of asubject through an anterior or posterior surgical procedure. The implant10 may be inserted through the anterior, posterior, lateral side, orforamin of the vertebrae. The implant 10 may be insertedtrans-pedicularly.

During a disc replacement procedure, at least a portion of the damagedor degenerated intervertebral disc is removed; the entire disc may beremoved in some aspects. The intervertebral disc space may then beshaped and prepared to receive the coiled implant 10, including shapingand preparation of vertebral endplate bone, if necessary. Once theintervertebral space is ready, at least one coiled implant 10 may beinserted into the prepared intervertebral space. The coiled implant 10may be inserted into the body as an uncoiled straight tube, for example,by housing the uncoiled implant 10 through a straight cannula, with thecannula inserted into the body. The implant 10 may then be released fromthe cannula, upon which the implant 10 will re-coil. The re-coiling maybe due to the thermal memory or super-elastic memory of the materialused to fabricate the implant 10.

During a vertebral body reconstruction procedure, at least a portion ofthe damaged or diseased vertebral body is removed (e.g., copectomy); theentire vertebral body may be removed in some aspects. The portion of thevertebral body may then be shaped and prepared to receive the coiledimplant 10. Once the intervertebral space is ready, at least one coiledimplant 10 may be inserted into the prepared portion of the vertebralbody. The coiled implant 10 may be inserted into the body as an uncoiledstraight tube, for example, by housing the uncoiled implant 10 through astraight cannula, with the cannula inserted into the body. The implant10 may then be released from the cannula, upon which the implant 10 willre-coil. The re-coiling may be due to the thermal memory orsuper-elastic memory of the material used to fabricate the implant 10.

Preparation of the vertebral area for insertion of the implant 10 maycomprise a cavity creation procedure. In such a procedure, thepractitioner forms a cavity around the local area surrounding the targetloci of the insert, for example, by pushing apart cancellous bone usinga cavity forming balloon (which is not the balloon 30 of the implant10). Once the cavity is formed, the cavity forming balloon may bedeflated and removed, leaving behind an enlarged space or cavity. Thiscavity reduces resistance that may accompany insertion of the implant10, including insertion via a cannula. In fact, the cavity may be usedto allow the straightened implant 10 to re-coil within the cavityaccording to its thermal or super-elastic memory.

More than one coiled implant 10 may be implanted into the intervertebralspace or into the vertebral body. Although one coiled implant 10 may beused in some aspects, two, or even three implants 10 may be implanted insome aspects. The coiled implant 10 may be placed at the anterior area,posterior area, or lateral area of the vertebral endplate, including inthe anterior-lateral or posterior-lateral areas of the vertebralendplate, see, e.g., FIG. 3A. Where more than one implant 10 is used,one implant 10 may be placed in the anterior area, and a second implant10 may be placed in the posterior area (see, e.g., FIG. 3B), or oneimplant 10 may be placed on one lateral area and the second implant 10may be placed in the opposing lateral area.

Once the implant 10 is in place, the balloon 30 or membrane 30 may befilled to a desired level with air or a fluid, thereby expanding theheight H of the coil by forcing the loops 16 that the balloon 30 ormembrane 30 touches to move upward and downward about the axis X of theimplant 10. The axis X preferably approximates the vertical orientationof the spine of the subject, for example, the vertical spine of a humanbeing that walks upright. In some aspects, for example, where thesubject is an animal that walks on four legs, the axis X may approximatethe horizontal orientation of the spine of the subject. The air or fluidmay be supplied by the second tool 200.

In some aspects, once the implant 10 is in place, but before the balloon30 or membrane 30 is filled with air or fluid, the balloon 30 ormembrane 30 may be filled with a contrast solution such as aradiocontrast solution, such that the coiling (if inserted uncoiled withcoiling in situ) and/or placement of the implant 10 may be visualizedand confirmed before permanence is established, for example, by fillingthe balloon with a permanent air or fluid and/or by deploying a bonegraft material or bone cement. Filling the balloon 30 or membrane 30with a contrast solution may also be used to visualize and confirm thatthe balloon 30 or membrane will properly deploy out of the gap 26 and/orinto spaces 18. The contrast solution is preferably removed from theballoon 30 or membrane 30 before the balloon 30 or membrane 30 is filledwith air or fluid.

The level of air or fluid may vary according to the needs of thesubject, including the proper restored height of the intervertebralspace, or the proper reconstructed height of the vertebral body. In someaspects, more than one balloon 30 or membrane 30 is present in thecoiled implant 10, or a single balloon 30 or membrane 30 with more thanone chamber is present in the coiled implant. In such aspects, a firstballoon 30 or membrane 30, or a first chamber of the balloon 30 ormembrane 30, may be filled to one level and at least a second balloon 30or membrane 30, or second chamber of the balloon 30 or membrane, may befilled to another level that is greater or less than the level of thefirst balloon 30 or membrane or first chamber, so as to establish alordotic angle in the intervertebral space. In other words, with oneballoon 30 or membrane 30, or with one chamber of a single balloon 30 ormembrane 30, filled to one level, and the other balloon 30 or membrane,or other chamber of a single balloon 30 or membrane 30, filled toanother level, the expanded height H of the coiled implant 10 differs onat least to sides and this difference in height H among these sidesestablishes a desired angle of lordosis.

Before, after, or concomitant with the filling of the balloon(s) 30 ormembrane(s) 30, a bone graft material may be deployed from the implant10. For example, a bone graft material may be inserted into an opening15 or 17, for example, by way of the first tool 100, into the lumen 22,out from the plurality of apertures 24 and, optionally also from theother opening 15 or 17, and into the intervertebral space. Upondeployment, the bone graft material may be present on and about theexterior of the coil, and/or may be present on and about the interior orthe coil, including the central void 19 established by the loops 16 andballoon 30 or membrane 30. In some aspects, the bone graft material ispre-loaded into the lumen 22, and air, water, or saline is forced intothe opening 15 or 17, thereby forcing the bone graft material out of theapertures 24. The bone graft material remains in place and facilitatesosseointegration of the implant, and in some aspects, may facilitatefusion of the adjacent vertebrae as bone begins to form off of the bonegraft material.

In some optional embodiments, the coiled implant 10 is removed from thesubject after the balloon 30 or membrane 30 is filled. In which case,the balloon 30 or membrane 30 is retained and supports disc replacementor vertebral body reconstruction. If the coiled implant 10 remains, theimplant 10 and balloon 30 or membrane 30 supports disc replacement orvertebral body reconstruction. The implant 10 and/or balloon 30 ormembrane 30 serve as the missing disc or missing vertebral bone untilosseointegration and fusion, mediated by bone graft material, proceedssufficiently.

The disclosure is not limited to the embodiments described andexemplified above, but is capable of variation and modification withinthe scope of the appended claims.

1-24. (canceled)
 25. A surgical method, comprising: inserting an implantinto a patient, the implant comprising an expandable hollow coil havinga first end, a second end, and sidewalls defining a lumen passingtherethrough, the lumen having at least one coiled balloon disposedtherein; and deploying the balloon from the lumen of the coil into atleast some of the spaces between adjacent loops of the coil to increasea height of the coil.
 26. The method of claim 25, wherein inserting theimplant comprises delivering the coil through a cannula while the coilis in an uncoiled state.
 27. The method of claim 25, further comprisinginserting a guidewire into the patient, wherein the implant is insertedover the guidewire and re-coiled as the guidewire is removed therefrom.28. The method of claim 25, wherein inserting the implant comprisesinserting the implant into a vertebral body.
 29. The method of claim 25,wherein inserting the implant comprises inserting the implant into anintervertebral disc space.
 30. The method of claim 25, wherein deployingthe balloon comprises inflating the balloon with a fluid.
 31. The methodof claim 25, wherein deploying the balloon restores a natural angle to adisc space in which the implant is disposed.
 32. The method of claim 31,wherein restoring the natural angle comprises filling a first balloon orchamber to one level and filling another balloon or chamber to anotherlevel.
 33. The method of claim 25, wherein the sidewall is C-shaped suchthat a gap is formed in the sidewall and wherein deploying the ballooncomprises deploying the balloon through the gap formed in the sidewall.34. The method of claim 25, further comprising delivering a bone graftmaterial or bone cement through the implant.
 35. The method of claim 34,wherein the bone graft material or bone cement is delivered to a centralvoid defined by the coil.
 36. The method of claim 34, further comprisingremoving the coil from the patient after delivering the bone graftmaterial or bone cement.
 37. The method of claim 36, wherein the balloonis left in the patient after the coil is removed.
 38. A surgical method,comprising: inserting an expandable coil into a patient, the expandablecoil comprising a hollow tube having a first end, a second end, andsidewalls that define a lumen, the hollow tube formed into a pluralityof loops stacked in a height dimension, the plurality of loops having aspace between lower and upper sidewalls of vertically adjacent loopssuch that the lumen has a coiled shape; deploying a balloon into atleast some of the spaces between vertically adjacent loops; and fillingthe balloon to expand the coil in the height dimension.
 39. The methodof claim 38, wherein the coil, when expanded, has a height thatapproximates the height of an intervertebral disc, the height of avertebral body, or the height of a spinal motion segment.
 40. The methodof claim 38, wherein the coil includes a plurality of apertures thatpass through the sidewalls and into the lumen.
 41. The method of claim38, wherein the sidewalls comprise a gap though the sidewalls and intothe lumen.
 42. The method of claim 41, wherein the gap runssubstantially the entire length of the coil.
 43. The method of claim 38,wherein the coil is inserted into the patient in an uncoiledorientation.
 44. The method of claim 38, further comprising deliveringbone graft material or bone cement through the lumen.